Conventional residential washing machines typically include an internal additive storage system that stores a bulk quantity of an additive (such as detergent, fabric softener, and so forth) and dispenses a metered quantity of the additive at a defined point in the wash cycle. These systems use an internal storage tank that must be accommodated in the tight space between the drum/tub and machine casing. Thus, the capacity of the storage tank is limited and requires frequent refilling by the consumer.
Also, with the conventional internal additive storage tanks, reliable liquid level sensing within the tank can be problematic due to the contoured and non-uniform shape of the tank. If the tanks are not readily visible to the consumer, relatively expensive sensing devices may be required to provide an accurate indication of the amount of additive left in the tank.
Accordingly, it would be desirable to provide a washing machine with an additive storage tank having increased capacity and a relatively simple but reliable liquid level sensor.